Living on the Land. Fundamentals of Weed Management. Andy Hulting. Oregon State University Weed Management Extension Specialist

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1 Living on the Land Fundamentals of Weed Management Andy Hulting Oregon State University Weed Management Extension Specialist

2 Evening Outline My Role With OSU And Contact Information Develop an appreciation for weed ecology/biology Can be useful to inform management strategies Discuss different types of management Weed Management Resources Extension Publications and Texts Questions And Discussion On Specific Weeds/Management Scenarios/Toxic Plants

3 Extension Weeds Specialist My Role at OSU 90 % Extension Appointment Facilitate Technology Transfer andrew.hulting@oregonstate.edu ph: Education and Outreach Resident Undergraduate and Graduate Training Stakeholder Groups 10 % Applied Research Program small grain, grass grown for seed, peppermint, oilseeds, pastures invasive species-knotweed spp., hare barley, others

4 Need to understand the biology and ecology of the weeds before you can really control them

5 Numerous Definitions of Weeds A plant out of place or not intentionally grown A plant that grows where it is not wanted A plant whose virtues have not yet been discovered A plant that is competitive, persistent and interferes with human activity Impacts are numerous

6 Negative Impacts of Weeds Quality and quantity of crop Increased time and effort to remove Human health Recreation value Livestock poisoning Need photo of garden weeds

7 Weed Classification Habitat Aquatic Terrestrial Parasitic Morphology Monocot Grasses and Sedges Dicot Broadleaf weeds Life cycle Annual Biennial Perennial Botanical Phylogenetic Latin name

8 Annual Life Cycle Many of the weeds we regularly encounter are annual weeds These plants reproduce by seeds Examples of annuals: common groundsel, bittercress, annual bluegrass

9 Reproduction via Seeds Seeds contain special adaptations to facilitate dispersal

10 Rob Dunn

11 Biennial Life Cycle Weed Examples of biennials: wild carrot, teasel, prickly lettuce Biennials reproduce via seed

13 Perennial weeds can be especially difficult to manage. The key is to consider when the plants are placing their reserves below ground.

14 Perennial Life Cycle Weed Examples of perennials: Canada thistle, dandelion, plantains Reproduces vegetatively and via seed

16 Vegetative Reproduction Rhizomes (modified underground stems) Stolons (runners) Perennials can also reproduce by: Stem tubers = enlarged rhizomes or stolons, also called nutlets Fragments

17 Weedy Plant Characteristics Rapid growth (germination to flowering in as little as six weeks) Seed dormancy Co-adapted to exploit human disturbance (e.g. prostrate growth habit & mowing) Vigorous vegetative reproduction or regeneration from fragments

21 Adaptive Management Process UNDERSTAND PROBLEM DEVELOP SOLUTIONS ADJUST SOLUTIONS, IF NECESSARY APPLY SOLUTIONS EVALUATE EFFECTIVENESS MONITOR RESULTS

22 Integrated Weed Management Prevention Cultural Control Physical Control Chemical Control Biological Control Apply weed control BEFORE plants go to seed!

23 Prevention Usually easier to prevent introduction of weeds than to manage established populations Clean tillage, mowing equipment Manure management Use clean feed and seed Monitor roadways, ditchbanks, etc.

24 Hand Pulling Mowing Plowing Digging Mulching Mechanical and Physical

25 Physical Control Mulch: Can build soil quality Conserves water Minimizes erosion Prevents emergence Must be weed seed free Mulch For Annuals, Not Perennials, Biennials

Perennials Small populations Biennials and some

26 Physical Control Hoeing Pulling For Biennials and simple Perennials Not Annuals, creeping Perennials Small populations Biennials and some perennials Caution: Disturbance can lead to new flush

Mowing Useful in reducing seed production, but won t kill many plants Can result in candelabra effect Many plants (Canada thistle, leafy spurge, tansy

27 Mowing Useful in reducing seed production, but won t kill many plants Can result in candelabra effect Many plants (Canada thistle, leafy spurge, tansy ragwort, sowthistle, and groundsel) have viable seed soon after flowering they must be cut before flowering stage For Annuals, Biennials Not Creeping Perennials

28 Annuals Growing Points Creeping Perennials Biennials Simple Perennials Arrows indicate lowest position on the plant from which new shoots can regenerate

29 Cultural Create environment for maximum crop/pasture competition against weeds Soil Fertility Crop Rotation Competitive Varieties Cover Crops Consider Planting Date and Rate Composting

30 Cultural Control-Soil Characteristics

31 Examples of weeds that often indicate poor growing conditions-modify your soil Weeds Knotweed, annual bluegrass Chickweed Dandelion Plantains Sedges Quackgrass Spurge Thistle spp. Wild carrot, garlic, onion Conditions Soil compaction, low soil oxygen levels Low soil N levels, thin grass Low fertility, drought, low mowing High soil ph Poor drainage, over watering Poor and/or sandy soil Low fertility, drought, Ca soils, low mowing Low fertility, drought, compaction Wet, heavy soils

32 Chemical Control Effective for spot treatments Effective on stubborn perennial weeds Recognize potential unintended effects

33 Herbicide Actions For a herbicide to be effective, it must 1) come in contact with a plant surface, 2) remain on the surface long enough to be absorbed, 3) reach a target site inside the plant in sufficient concentrations to disrupt a physiological process or development. Contact Absorption Translocate

34 Herbicide Types Systemic travel through plant s vascular system to reach site of action interfere with the plant s physiological and metabolic processes glyphosate (Roundup type products) Contact penetrate the cuticle and act in leaves and shoots kill by acute toxicity acetic acid

35 Weed B Gon MAX, PAR III, Trillion, Tri-Kil, Killex Mimics the effect of plant hormones and causes the plant to grow uncontrollably which leads to abnormal growth and in some plants death. Only effective on broadleaf (dicot) weeds Will not affect lawns In the soil 2,4-D has a half life of less than 7 days and in water it is broken down in one to several weeks 2,4-D

GLYPHOSATE RoundUp, Rodeo, Pondmaster, Accord Interferes with amino acid synthesis and therefore affects young growth areas of the plant Glyphosate is effective on grasses, broadleaf

36 GLYPHOSATE RoundUp, Rodeo, Pondmaster, Accord Interferes with amino acid synthesis and therefore affects young growth areas of the plant Glyphosate is effective on grasses, broadleaf species, and some woody species. Systemic herbicide so application must be at a time when plant is actively growing. Half life ranges from 1 to 174 days in soil, and 12 to 70 days in water.

Limonene GreenMatch, Nature's Avenger Many herbicides

of the leaf surface and cause dessication.

37 Limonene GreenMatch, Nature's Avenger Many herbicides labeled for organic production (like Limonene) are contact herbicides. They are strong acids that burn holes in the cuticle of the leaf surface and cause dessication. Should be applied with caution because it is non-selective. Can cause short-term change in soil ph

38 Contact Herbicides Contact herbicides destroy cell membranes or interfere with cell division. Because a contact herbicide only affects tissue to which it is applied, complete coverage is essential. Not as effective on perennial weeds or grasses and most effective on SMALL broadleaf weeds Symptoms from a contact herbicide applied over soybeans.

39 Biological Control Use of other living organisms for the management of certain weed species Insects Diseases Livestock Long-term approach Some success stories

40 Oregon Department of Agriculture Noxious Weed Control Program Eradication of new, small infestations Biological control of widespread weeds (110 control agents, 32 weed species) Oregon State Weed Board designates state noxious weeds and provides grants to local agencies and organizations

41 Mechanical + Chemical Control Tomato Transplants

42 Example IPM -Canada Thistle (Cirsium arvense) A perennial that reproduces from rhizomes and seed Infests crops, pastures, rangelands, golf courses, lawns, etc. One plant can colonize a 1-2 m diameter area Seed are produced, but sparingly (1,000 per shoot) through obligate outcrossing (plants are either male or female) Vertical roots grow 2-5 m; horizontal roots grow up to 5 m Produces up to 8 reproductive buds per meter of rhizome Rhizome fragments as small as 0.5 cm have sufficient carbohydrate reserves to produce a new plant

43 Masiunas et al. (Univ. of IL) Summer annual smother crops to suppress Canada thistle (and other perennial weeds)? Much research has been done with winter annual cover crops-winter wheat, cereal rye, hairy vetch, etc. Are summer annuals more suppressive time growth to maximize competition with CT to deplete carbohydrate root reserves to prevent regrowth and patch spread Willingness on part of the grower to sacrifice returns from cash crop to manage CT patches

Previous crop: organic alfalfa Frequent dairy manure applications Canada thistle patches measured, plants counted and field disked in May Early June Sweetleaf II sterile sudangrass seeded with a

44 Previous crop: organic alfalfa Frequent dairy manure applications Canada thistle patches measured, plants counted and field disked in May Early June Sweetleaf II sterile sudangrass seeded with a drill at ~ 60 lbs/a First flail mowing: CT had flower buds and sudangrass was 4-5 tall 2 nd mowing occurred in August Fall mowing and tillage CT density measured the following year in a soybean crop Treatment Details

45 Results and Recommendations When Not Using Herbicides CT density (~ 90 %) and mass were reduced Competition for light and possibly allelopathy from sudangrass root and shoot exudates Prevent new CT patches Dedicated, frequent and intensive fall and spring tillage summer sudangrass crop can be mowed twice harvest forage or create surface mulch mowing will prevent flowering of CT that does emerge multiple year process and costs

46 Summary Learn to recognize common weed species on your farms or on your property Familiarize yourself with biology of that plant Utilize adaptive management strategy Prevention is key Integrated strategy that suits your goals and lifestyle Adopt a long-term strategy/outlook Learn to accept presence of some weeds

48 Resource Recommendations Online Weed ID: PNW Handbook

50 OSU Extension Publications Catalog PNW 613 Rattail Fescue

53 Discussion of Problem Weeds

55 Poisonous Plants Often a component of rangeland, pastures and hay fields can be native or exotic, common or rare toxicity may vary between plant growth stages, sites and years Potentially dangerous to livestock Toxins related to complex secondary plant compounds Livestock will often avoid, but inadvertent consumption (hay or silage or lush pasture) extreme overgrazing Damage can be minimized basic understanding of the plant species and occurrence integrated management of livestock and toxic species

What is a Secondary Compound Definition complex organic molecules that are not directly involved in metabolism (Whittaker and Feeny 1971) They can play a role in pathway regulation (respiration and

56 What is a Secondary Compound Definition complex organic molecules that are not directly involved in metabolism (Whittaker and Feeny 1971) They can play a role in pathway regulation (respiration and photosynthesis), protection from the environment (UV rays, drought), act as storage of important compounds (nitrogen in legumes), physiology (carotenoids that provide color), or be toxins. Seigler and Price 1976 American Naturalist 110: Found mostly in organisms without immune systems plants, fungi, microorganisms. Whittaker and Feeny 1971 Science 171:

57 General Management Recommendations Improvement of rangeland and pastures minimize overgrazing, forage selection, fertility, etc. Know the locations of toxic plant populations Targeted management of the plant population preventative, cultural, physical, chemical and biocontrol Management of the affected livestock Limit exposure-timing of grazing most poisonings occur in early spring or late fall moving or fencing off animals Differential tolerances (sheep vs. cattle vs. goats)

58 Western Bracken Fern Perennial Solitary Creeping rhizomes Dense hair on undersides of fronds Brown spores on undersides of frond segments New growth as fiddlenecks

59 Horses primarily, swine, cows and sheep also affected Principle toxin: Thiaminase, ptaquiloside Thiaminase causes Vitamin-B deficiency in horses and swine if eaten in large quantities (symptoms as for Equisetum spp.) Ptaquiloside is a carcinogen that can affect cows Can cause blindness in sheep Newly emerging fiddleheads are especially toxic, however animals must eat their weight over several months for disease to develop Toxins remain in hay and silage Not highly palatable

60 Senecio spp. Difficult to differentiate species Genus characterized by nonoverlapping bracts around flower Pinnately divided leaves Yellow ray flowers in terminal clusters

61 All livestock affected Principle toxin: Pyrrolizidine alkaloids Young plants are most toxic Can cause acute liver necrosis and death or chronic liver damage if eaten in small amounts over a long time period Not palatable unless no other forage is present Remains toxic in hay

62 Buttercups Various Deeply lobed leaves 5-petaled yellow flowers

63 Sheep and cattle affected Principle toxin: Protoanemonin from ranunculin glycoside Toxin is released when plant is chewed Causes blistered mouth, excessive salivation and intestinal irritation which can result in diarrhea. Can be fatal if eaten in excessive quantities Can reduce milk production Creeping buttercup is toxic to cattle; bur buttercup is toxic to sheep Toxin lost in dried forage Not palatable; generally avoided

64 Docks Perennial Swollen stem nodes Membranous, sheathing stipules Flowers in whorls at upper stem nodes Fruit in 3-winged perianth

65 Sheep and horses affected most; cattle less susceptible Principle toxin: Oxalate accumulator Not a common source of oxalate poisoning, but will be toxic if eaten in large quantities May cause irritation to skin and digestive tract; dangerous levels are rare Can cause hypocalcaemia Dock in silage is not a critical problem as long as it is diluted with plenty of other feed Calcium supplements will bind with oxalates and make them insoluble

66 Poisonous Plant Management Links Fact sheet supporting horse farm publication for central and eastern Oregon: Here are some other references: Cornell University Poisonous Plants Informational Database. Guide to Poisonous Plants (Colorado State University). index.cfm Horse Owner s Field Guide to Toxic Plants, Sandra Burger (Breakthrough Publications, 1996). The USDA ARS Poisonous Plant Research Laboratory. USDA Natural Resources Conservation Service Plant Links. Poisonous and Medicinal Plants. Weeds of the West (Western Society of Weed Science, revised 2001) Weeds of California and Other Western States (University of California Press, 2007) The Pacific Northwest Weed Management Handbook.

TANSY RAGWORT. a Paid-of/ma 20eed. Rex Warren Virgil Freed. Extension Bulletin 717 May 1951

TANSY RAGWORT. a Paid-of/ma 20eed. Rex Warren Virgil Freed. Extension Bulletin 717 May 1951 TANSY RAGWORT a Paid-of/ma 20eed Rex Warren Virgil Freed MATURE PLANT FEDERAL COOPERATIVE EXTENSION SERVICE, OREGON STATE COLLEGE, CORVALLIS Cooperative Extension Work in Agriculture and Home Economics,